Is there a quick & easy way to inspect the diff?

Hudson is a great care-giver...........Thanks for the relief!....;-)

Recouperating Me

 

Ahhhh, the diff (and belt) discussion, once again.

How many diff failures have been documented during the 1974 through 1995 run of flat 12's?

How many have suffered a collision with another vehicle or stationary object?

I believe there is far greater danger of an accident than a diff failure. Take home lesson? Don't drive the car!

Sure, insurance will pay for the collision damage, but the depreciation in resale (assuming not totaled) will likely exceed the cost of a diff failure.

And if I may quote Big Red, "I think the TR diff is not a matter of if, but just when -...." The same can be said about what appears to be a successful U.S. blockaid to rid Cuba of Castro. It is sure to work, just a question of when.

Of the 10,000+ examples of flat 12 diff's driven during the past 30+ years, perhaps a handful have failed. Those that had a bad weld have likely declared themselves. The remaining majority, like Castro, will eventually require an engine out owing to failure of some other mechanical part (valves, cams, synchronizer, etc.), but not before the car is owned by someone else. Statistically, most of you will sell the car sometime before the next 50 years has elapsed.

The diff and belt issue is of great value to someone purchasing a car (bargaining point), of little value to someone selling a car (compromise required), and enormous value to someone paid to service the car (kid's need shoes).

Jim S.

 

Hello "A"; Thanks for the link. VERY INFORMATIVE....Sorry to open up an old wound Kerry. like asking someone to relive their horrid divorce, at least not as expensive, & the Testarossa is better than an "Ex"...at least you still enjoy...."Playing with the Testarossa".....Mark

 

Unfortunately I have to report the failure of my diff just last Thursday. Less than 1 km from home, just leaving the forecourt of the petrol station and it just didn't feel right. Shifted into second and the car felt like the gear didnt engage, slowed and turned into a side street and saw a trail of oil behind me. By the time I parked and got out the pool of oil was 16" wide and growing. Total loss of drive.

My car has done close to 45000 kms, gets driven regularly, has never had the clutch dropped hard enough to provoke wheelspin and has had only two mature owners.

So given the way that I baby my car, especially when it's cold, I'd say that the age old adage of 'not if but when', still applies. My car has done 750 kms since it's engine out major and given it's condition and low mileage, we didn't even consider doing the diff at that time.

BIG MISTAKE!!!

 

Dropped the rear sump plug on the gearbox today and extracted two of the left side roller bearings. Crownwheel teeth look okay but obviously something has caused it to lunch the entire left roller bearing into a zillion bits.

More to follow as the mess unravels.

 

Ugh. So sorry to hear. Which car is it? The 88.5? Were the changes to the 'TR' carrier inclusive of the internals such as the bearing issue? Either way, hope your solution goes as smooth as can be expected.

 

Robert, Sorry to hear that also.
If I'm not mistaken, the weld on the carrier is on the left side.
Please let us all know what you find, and even pictures, if possible.
John

 

Yes, unfortunately it was my beautiful red 88.5

I only have a four post lift in the garage which is esentially a car stacker, and I'm exploring ways that I may be able to use this to slip the engine out.

I was going to try and do the job in the car but there are two of the LHS exhaust manifold bolts that look like they have experienced 100 years of climatic extremes. In fact one nut is not even identifiable as a nut anymore, just a blob of rusted steel, so I don't think I could ever get the exhaust off with the engine in the car. It's going to take some skillful surgery and then I will want to replace a few rusted studs properly as well before re-assembly.

I'll keep this thread updated as information becomes available.

 

This post gave me nightmares last night.
So sorry to hear.

 

I heard of a guy with a 355 do this.

1) Back the TR off the end of the lift onto planks built up to the same level as the ramps.
2) Back it off far enough that the sub-frame separation point will easily clear the end of the lift.
3) Place jack stands and/or solid blocks of wood and shims under the frame at major frame points FORWARD of the the separation point of the sub-frame. (4 places if possible)
Note: Balance-wise, this isn't any worse than putting it on a two-post lift.
4) Strap the front suspension of the TR to the lift. Nylon straps will work. The force wouldn't be that high.
5) Leave the rear wheels on the car.
6) Disconnect all umbilicals from the engine etc......
7) Place casters under the forward half of the sub-frame.
8) Raise lift with car on it. Leave engine on the ground.
9) Roll engine aft.
10) Cherry-pick it onto your bench or cart. (Estimate weight with frame and trans at 1400 lbs.)

 

Yep, my mate Mike in Sydney did his Testa on his 4 post hoist that way also. Apparently it's not great for the chassis to lift the car whilst all that rear weight is hanging off the back so I have to work through that part yet.

Even just removing the rear wheels and axle assemblies will seriouslycut the weight down though.

 

Same over here: carefully driven......., but I am sure you have read that in my posting already ...

Good Luck ...

 

I would have concerns about the cantilevered weight as well but just how much different would it be from the typical pick-up points of a two-post?

I am thinking most of the disconnects can be accomplished while the car is entirely on the lift, including mounting the casters to the front of the sub-frame members, then roll it off at the last minute to raise the body.

You should be able to snake underneath for the last couple of bolts in the subframe at that point.

BTW Robert, I am terribly sorry to hear about this happening. Makes me sick to my stomach.
I have made the decision to quit rolling the dice and fix the possibility during my 30k.

 

A oil analysis of trans fluid would tell of high particle metals content, especially if this was done once a year a change would indicate impending failure before a major failure, heavy expensive equipment has this done all the time to prevent a mass failure

 

I agree to the process you describe but in many cases the cracks form without causing any misalignments and resulting metal deposits until the fateful day of catastrophic failure.

There is a thread here somewhere (maybe this one) where a differential was inspected during a 30k on a TR that was showing no indications of failure. The car ran and shifted fine.
Visual inspection showed a nasty crack around the left side of the carrier.
The pin on the grenade had been pulled.

 

I took a quick look by removing the rear most 42mm sump plug. It was completely coated in filings of metal and one big lump about 14 x 9 mm in size. When I wiped it all off, it is a roller bearing from the collapsed main carrier bearing.

I dumped all the trans oil and found another bearing and bits of the bearing cradle.

With both wheels off the ground I rotated one wheel slowly and I can see probably 3/4 of the crown wheel teeth and they look okay, but then again, it only takes one to be rooted and I'm in the **** big time.

When I can figure out how to safely support the car and get the time to strip it down I'll report back in with the extent of the damage.

 

Here's hoping the damage is somewhat limited.
You don't deserve this considering how your car has been treated over it's life.. (actually, nobody does).

I just ordered a carrier for myself from Newman this morning.
Although my TR is running and shifting fine there is no telling what is going on in there.

The way I see it there are three choices a TR owner can make:
1) Roll the dice and continue to drive as is.
2) Succumb to the fear and sell the car at a loss (due to soft market and the reputation of the defect etc...)
3) Commit to ownership and make a pre-emptive upgrade.

Obviously I chose #3 and the TR will remain parked until it goes in for it's 30k.
I am guessing the pre-emptive upgrade should cost maybe 1/3 of the repair after the fact, possibly less..

As much as I would like to have a 550, it just doesn't have the same visual impact as a TR, though I must say, the torque in the 550 is addictive. Maybe down the road...............................

 

I like to consider myself committed to ownership. I am about as anal as anyone I can think of. I based my decision not to do the replacement during my exhaustive service on a variety of factors, including the visual inspection of the carrier, the service history of the car, the reputation of the prior owner, the condition of the car, the mileage of the car, and most importantly, information gleaned from conversations with more than a few f-car master mechanics whom I have relationships with. FWIW, I have been advised that the welded carrier has been in continuous use by Ferrari since the 275 IIRC -- many of which were tracked within an inch of their lives. Among recent Ferraris, there are probably over 8500 testarossas and early TRs that share this diff, in addition to the Boxers.

I'm not saying they don't fail, I just don't believe they fail with the frequency that is perceived on this board.

Just my .02

 

I understand your decision to go with what you have based on your inspection. I probably would have done the same thing.
Unfortunately, I haven't had the opportunity to inspect the carrier on my TR so in effect, it's an unknown quantity.

I would also hesitate to compare the welded differential in a TR/ Boxer to any other welded Ferrari differential. The variables of weight, horsepower, design and type of construction makes it apples to oranges. ( A 275 Diff doesn't have an engine and transmission sitting on it.)

I have been reading all sides of this issue for the last 6 years and was well aware of the potentials when I bought my TR. I have maintained pretty much the same reasoning that you state above, up until this week.

Perception is based on evidence. Collection of evidence and the accuracy of evidence changes perception as the data changes.

Four years ago hardly anyone "heard" about the failures, at least, not with great frequency. That doesn't mean there weren't more than what we were "hearing" about.

In the last year we have been hearing about more failures than ever.
My perception has changed.

To me the risk and expense of a catastrophic failure outweighs the popular perception that, "It doesn't happen that often".
That may be true................................ but MINE might be the exception.

It's not just the carrier that breaks. The transaxle housing breaks, transmission parts break, gears break.

Don't forget that parts for these are getting harder to find and because of that the price to repair goes up.

Personally I don't have the 10 to 15,000 laying around in the event my transaxle blows it's guts out.

Therefore I have chosen to make a pre-emptive move so I can fully enjoy my TR without that niggling voice in the back of my head saying, "Is it going to happen this time?".

This is a choice I have made for my own piece of mind. Nobody has to agree with it, but then, NOBODY is going to pay the bill when it breaks either.

Take a look at post #4 of this Fchat link. I know this car, http://www.thebestemployee.com/forum/showthread.php?t=348647

 

I understand where you are coming from and I don't mean to be flippant or minimize the potential for catastrophic failure. Admittedly, it will be something I will tend to at some point in the future-- but in light of what I know about my car and what I have learned, I just don't have the feeling of urgency that others do regarding this problem.

As for the data, you may be right, but don't discount the possibility that the popularity of this site and others like it have lead to an increase in reporting of the problem, not necessarily the frequency. In other words, the information obtained on this site may ultimately be merely anecdotal.

Nonetheless, I will never fault another owner for taking the bull by the horns and doing preventative maintenance. There is a value in having peace of mind, and your repair will only increase the reliability and desirability of your car down the road.

Good luck!

 

I wish you well Joe.

My car came out of the UK with 12k miles on it. A one owner car driven by an elderly English aristocrat with full service history and in very nice condition.

The car has been meticulously maintained by me in the four 1/2 years of ownership even though I've done 25k kms in it. Diff oil every year, engine oil every 5000. Never even one wheelspin start, no heavy clutch dumping.

If ever a car wasn't going to ever do its diff I expected it t be mine as I was just so aware of the entire issue.

And here we are............................

My advice, do the damn diff before it breaks because it will either break your heart or your wallet or both. It's not a matter of if, it's a matter of when.

 

So a bit of an update. I borrowed a small Snap On borescope tonight and had a look up the rear most sump plug hole.

The side bearing on the LHS has completely destroyed itself. All of the roller bearings have gone and the bearing race itself looks very seriously burnished (from heat?)

The bearing cage has disintegrated and there are bits of it everywhere. I located two more roller bearings inside a casting cavity that I can't identify yet.

There is a large portion of a circular flange shattered and dropped into the lower recess of the box. This appears to be from the side carrier. So far the crownwheel looks okay but I can't see the pinion.

So what let go, the diff or the bearing? Hard to tell yet. Whatever happened it's quite cataclysmic. There appears to be no damage to the actual gearbox casing apart from one triangulated gusset has a small chunk taken out of it. Looks like that will be a simple weld job.

The rest...........just plain nasty.

 

I am looking into sorting mine sooner rather than later now I know that both you and Mel have had problems.
Hope its not too expensive!

Are you going to do one of your fantastic write ups on the rebuild Robert?

When I do my rebuild I will post up the same although it will probably be next winter when I get round to it as I have enough to do this winter including work on Lynda's XK

P

 

I'll do my best to document it and will probably put it up on my web site. I think it's pretty important that detailed information pertaining to this job is made available to the Testa community rather than the occasional picture that we see of the rare broken diff that is actually repaired by a home mechanic rather than a dealer or pro shop.

General, a shop will just get it done and we miss out on the documenting of the job and the pics along the way.

I know that I've looked at the exploded parts diagrams and tried to grab as many pictures as I can locate off the web to assist me in identifiying the parts that I'm likeley to need, but it's still a serious grey area.

 

Robert,

Could you view the weld on the Diff. carrier with the borescope?



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